A considerable research effort has been directed to the development of new cephalosporin compounds for the treatment of infectious diseases in man. Most recently it has been disclosed that certain cephalosporins bearing a 2-(2-aminothiazol-4-yl)-2-methoxyiminoacetamido substituent at C-7 and substituents including acetoxymethyl, carbamoyloxymethyl, (1-methyl-tetrazol-5-ylthio)methyl and (1,3,4-thiadiazol-2-ylthio)methyl at C-3, exhibit activity against both Gram positive and Gram negative microorganisms (Belgian Patent Nos. 852,860, 852,971, 850,662 and 853,545, West German Offen. No. 2,704,712, and Japanese Application No. 125,826/1976).
This invention relates to a new class of cephalosporin compounds. More particularly this invention relates to cephalosporins having a 2-(2-aminothiazol-4-yl)-2-(hydroxy or C.sub.1 -C.sub.4 alkoxy)iminoacetamido group at C-7 and a 4-(C.sub.1 -C.sub.4 alkyl)-5-oxo-6-hydroxy-4,5-dihydro-1,2,4-triazin-3-ylthio)-methyl group at C-3. The compounds of this invention exhibit excellent broad spectrum Gram positive and Gram negative antibiotic activity. The present compounds exhibit superior antibiotic activity, especially against Gram positive microorganisms, when compared with other cephalosporin compounds, including the recently disclosed cephalosporins having a C-7 2-(2-aminothiazol-4-yl)-2-alkoxyiminoacetamido substituent.
Broadly the compounds of this invention have the formula ##STR2## wherein R is hydrogen, an alkali metal cation, or a carboxylic acid protecting group; R.sub.1 is hydrogen or methoxy; R.sub.2 is hydrogen or an amino protecting group; R.sub.3 is hydrogen or C.sub.1 -C.sub.4 alkyl; and R.sub.4 is C.sub.1 -C.sub.4 alkyl.